SHARES in sleep apnoea equipment maker ResMed were pushed to adjusted all-time highs on Friday as investors reacted positively to record earnings in the December quarter, and as the company flagged a continued robust earnings outlook.

Driven by buoyant sales of high-margin products, earnings a share hit US53¢ in the December quarter up from US42¢ a year earlier, which pushed December-half earnings a share to $US1.02 up from US75¢.

Revenue for the quarter surged to $US376.5 million from $US332.7 million, reaching $US716.3 million for the half, up from $US647.5 million.

Revenue growth remained strongest in the US, rising 16 per cent in the quarter, well ahead of the 10 per cent growth elsewhere.

Unit sales in Europe are growing at 4-6 per cent, 6-8 per cent in the US and 8-10 per cent in Asia and the Pacific, the company said.

With the strong Australian dollar, production and assembly in Singapore now accounts for more than half of all units sold, which will rise over time to an estimated 75 per cent, the company told analysts.

Along with its production of high-end units in Australia, ResMed produces some low-end products such as masks in Malaysia.

Optimism for its outlook, along with speculation a weaker Australian dollar will help push earnings further ahead helped to push its shares to new highs of $4.60 before easing slightly to finish at $4.58, up 30¢. Its shares traded at $2.50 a year ago.

''These guys are industry best. They are great strategists,'' said Wilson HTM analyst Shane Storey said of the results.

''It's had a great quarter, but the current quarter will be up against very strong year-earlier numbers'', which may make growth comparisons difficult.

The strong gross profit margins at 60-62 per cent, coupled with low tax levels thanks to operations which are spread across Asia and Australia, also helped spark investor interest on Friday, analysts said.

Even after buying back 1 million shares during the quarter, ResMed had a net $US657 million in cash sitting on its balance sheet at the end of December. It flagged buying back another 1 million shares in the next six months.

A US17¢-a-share dividend was declared, with holders of its Australian-listed scrip entitled to a US1.7¢-a-share dividend.